As methods for producing polyfluoropropionyl halides, (1) a method of oxidizing 1,1,1,3-tetrachlorotetrafluoropropane with fuming sulfuric acid in the presence of a halogen and under irradiation with light (Japanese Unexamined Patent Publication No. 237040/1985), and (2) a method by electrolytic fluorination of butyryl fluoride (U.S. Pat. No. 2,717,871) are, for example, known.
The method (1) can not be regarded as an industrial method, since a waste acid containing chlorine is formed in a large amount as a by-product. On the other hand, the method (2) can not be regarded as an economical method, since a large quantity of electric power is required, and a cost is required for separation from hydrogen gas formed as a by-product.